CVE-2026-53646 FOSSBilling: Client password reset token reuse allows persistent account takeover
Attackers can reuse old password reset tokens to take over accounts because the system fails to invalidate previous tokens when new ones are requested.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-53646?
CVE-2026-53646 is a high-severity vulnerability in FOSSBilling, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
FOSSBilling is a free, open-source billing and client management system. In versions 0.5.6 through 0.7.2, when a `ClientPasswordReset` record already exists for a client (from a previous unexpired reset request), subsequent calls to the `reset_password` guest API endpoint reuse the existing token instead of generating a new one. The 15-minute validity window is anchored to the first request's `created_at` timestamp, not the time of the most recent email. An attacker who obtained the original reset link remains able to use it even after the victim requests a new reset, because the original token is never invalidated or rotated. Version 0.8.0 patches the issue. Some workarounds are available. Configure a reverse proxy (e.g., Nginx, Apache, Cloudflare) to apply per-IP rate limiting to the `/client/reset-password` endpoint to minimize the window of opportunity, and/or manually clear expired `client_password_reset` records from the database after a client reports a suspected compromise.
Weakness: CWE-640
Which versions are affected by CVE-2026-53646?
How do I fix CVE-2026-53646?
No fix has been published for CVE-2026-53646 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-53646 being exploited?
There is no known exploitation of CVE-2026-53646 in the wild and no public exploit code.
Sources
Also known as GHSA-vp66-w6rc-x32p.